This invention relates to an improved broadband radio frequency antenna operable through a window in an ablative heat shield of a reentry vehicle.
The U.S. Pat. No. (4,006,480) describes an antenna window which functions in the ablative environment of a vehicle reentering the atmosphere from space. Charette et al disclose a window whose forward edge is below the level of the heat shield while the trailing edge of the window is raised above the level of the adjacent heat shield. The resulting abrupt steps at the window-heat shield interfaces diverts air flow precluding severe local material loss due to differences in the ablation rates of the two materials.
In U.S. Pat. No. 3,739,386 to Jones an antenna for a space projectile is disclosed comprising a plurality of concentric ring radiating elements situated in the base of the vehicle. Each radiating element is a plated, dielectric loaded cavity extending around the circumference of the ring. The elements may be stacked and collectively phased to produce a desired radiation pattern.
Neither of these patents disclose the purpose of the subject invention which is to provide an antenna which can transmit and receive information over a wide frequency range through a window in an ablative heat shield.